(image from one of my favorite sci-fi games)
There have been made materials effectively invisible to photons (light) of certain frequencies. Metamaterial cloaking is the term. It is not unreasonable to expect that in time, a civilization can make materials that are invisible to a wide range of frequencies of light, for example all the visible light spectrum. Can you imagine what story elements it opens up if cloaked invisible items are cloaked by default when built? But instead even sci-fi published tomorrow and I bet ten years from now, still maintains the premise that cloaking of any sort is done with a “field” of some sort, and that if you stop putting energy or effort into that field, then the object reverts back to its default visible state. It may be a natural assumption to make, because objects are generally visible as their default state, but sci-fi writers should keep up with cutting edge science. Or else they can no longer call their work “science fiction”, it will just be fiction. Or maybe we need to invent a new genre, some designation which means; “this would be science fiction if written long ago”.
Another thing; Aging is comprised of seven biological processes, which are the causes of the diseases old people get (cancer, cardiovascular disease, dementia, arthritis, diabetes, wrinkles, etc). There’s a huge field devoted to intervening in these processes, called rejuvenation biotechnology. These scientists expect (not hope) that the first person to live to a thousand years of age (looking 25), is already alive today. Simply because if you successfully give one set of rejuvenation treatments, you buy decades to improve on these treatments. After all, they are rejuvenating the patient to a younger state, not just slowing aging a bit. So if you’re 60 and are just rejuvenated by 1/6th, then you presumably still have some 30 odd years for us to improve on the treatment. Once we can rejuvenate you 30 years every 30 years, you have reached “longevity escape velocity” (LEV), since you can presumably remain young indefinitely then.
You may argue all day about when a civilization’s technological development reaches LEV, but a civilization is going to reach LEV long before they become an interstellar civilization. All civilizations with type 1 kardashev scale status, will have reached LEV. There may be population within that civilization that for whatever reason chooses to not take rejuvenation treatments and die from cancer, cardiovascular disease, dementia and so forth, but the ones you meet out there among the stars, will mostly have LEV. To not have LEV in the civilization you write about in your science fiction work, must be explained thoroughly. Maybe the civilization has some religious objection or has a violent nature where murder is so commonplace and accepted that people just never encounter aging, no matter what it is, it must be explained. Or else we may just think you don’t have LEV because of your ignorance about 21st century science.
I must point out that LEV offers an innumerable amount of new stories to be told. I am utterly sick and tired of reading about civilizations without LEV. Even my favorite computer-game trilogy Mass Effect would be ten times better if LEV was in there. It very nearly is in there in the form of two species that live a very long time (Krogan and Asari), but then we can’t explore what the industrious Salarians would do with LEV. The Salarians have very short lives normally, so they act and think fast, though act wisely, and they would keep this fast-paced behavior with LEV, but they would each have centuries more expertise and practice at wise quick action. Now that would be an interesting civilization. Furthermore, the Geth, a civilization of artificial lifeforms, they have LEV, effectively, but we never hear about them from that perspective. Probably because the writers are human beings without LEV, incapable of thinking of thinking about it from an LEV perspective without a prompting (or swift ass kick) such as this post right here.
Even if your story doesn’t use LEV itself as a main story element, its still going to be a huge part of the world. For example, Faster Than Light (FTL) travel is going to be measured in use against slower than light travel (STL). Because not everyone in the civilization can afford to go quickly, because it takes an enormous amount of energy. Whereas some can’t afford to go slowly, because they are psychologically incapable and/or their task has a pressing time schedule. Interestingly there will be an elite group in both groups. The slow travelers will have an elite who go slow because they’re mentally fit for it and because they are wise enough not to waste their accumulated resources just to “drive fast” (if you have a lot of stuff to bring with you it costs more to go fast than if you don’t have a lot of stuff to bring with you). And the other elite will go fast because they’ll be getting a lot for their trouble if they get where they’re going, very quickly. The poorest will be the ones in the middle of the speed at which they travel between solar systems and galaxies. Those who don’t own so much stuff that its very costly to go a little bit quickly, but they don’t get so much in return when they get to their destination that its worth going really fast.
FYI; Any civilization is going to have LEV before they have FTL. So even if they travel around like a Star Trek spaceship at your point in the story, they made the first interstellar colonization efforts with STL travel and patience. That should give you some indication that if you want to write warlike and rash aggressive species into your story, then you need to remember that their aggression and warring behavior is going to have a significant patient agenda and plan behind it. Even if individuals your characters meet, stick out as short-sighted simpletons, the real movers and shakers will by necessity be the ones who had long term plans and patience. Because the ones with less forward-looking plans were murdered and otherwise disposed of as leader material by the ones in power when your story happens. LEV affords “baddies” a whole swath of new ingenious ways to patiently succeed with evil plans.
Space farming. There is just no actual need for an interstellar civilization bring an actual farm into space, nor do farming where they settle. Already now people like Solar Foods are making nutrients artificially. And therefore big space farms and generational ships and such, that’s just dead, that’s stuff for sci-fi works in the past, not sci-fi written today. Interstellar civilizations probably use some amount of space farming to boost morale, but their primary dietary requirements will be met from artificially created nutrients. It should be mentioned that there’s no real reason you would, in an interstellar civilization, be able to distinguish bread made from artificial starch from the “real” thing. Sure we may be able to distinguish between artificial meat and the real thing today, but we’re not even a planetary civilization (we don’t truly control even one planet), an interstellar civilization controls many solar systems. So their artificial nutrient technology will be sufficiently advanced so that the only way to tell is cost of the food (Insert the new cliche scene where someone sells an artificial steak or bread as the real deal, to make it clear to the reader how untrustworthy he is).
Onto another topic. Sci-fi writers tend to assume that evolved behavior will still be present very much in interstellar species. By that I mean that the species innately falls into fallacious arguments and make decisions largely based on cognitive biases. It should be noted that these cognitive biases are largely based around saving calories by making intellectual shortcuts.
An interstellar civilization is going to have something called introspectral magnitude levels (spectre levels for short). Spectre level zero is when you make a decision to the best of your ability. Spectre level one is when you take a look at the brainscan data of your spectre level zero decision, and use that data which perfectly points out every molecular event that led to your decision, to make a new decision to the best of your ability. That decision may be the same as the previous one, but it won’t be based on the same reasons, if that is the case. Spectre level two is when you again take a look at the brainscan data from spectre level one, to make a new decision, and so on and so forth. This is the only reliable way to control the quality of the actions of your deterministic brain.
Right now, most human beings could spend thousands more calories a day on the decisions we make. But we still have tons of cognitive biases, every one of which makes some energy-shortcut in our thinking. The biggest fundamental difference between a primitive civilization and an advanced civilization, will be how much more energy their brain consumes. How much energy the brain allows itself to consume on a decision (before making a stupid one), how much energy the brain allows itself to consume on trying to think of a novel solution (before giving up), how much energy the brain allows itself to consume while discussing with other brains (before punching them in the face). Therefore, in the opening moments of a book I do not want to see a so-called “very advanced civilization”, reach something called terminal conversation value.
I wrote this because I hope to one day read sci-fi where I don’t feel like it was written in the 1800s.
PS: In a hundred billion years or so, travel between galaxies is going to become impractical because of the expansion of the universe. So at least some portion of the civilization you write about, is going to be intent on making preparations for surviving the eventual end of the universe. Maybe none will be mentally fit to exist for that long, but some will certainly give it a good try.
PPS: A brain doesn’t fill up with memories, you just forget memories that the brain hasn’t spent calories maintaining.
PPPS: To make it clear, with LEV you’d literally look 25 years old, not older and older until you sit inside a hollow curved horn on the wall.
PPPPS: There’s no one who would force you to work your current job for 150 billion years, unless you are stupid enough to take up a loan that you thought you’d never have to pay back, “Because I’ll be long dead by the time I have to start payments on this loan”. If that happens then maybe they’ll put you in a suicide-watch type living-arrangement, so that you can not escape your debt when you realize you can’t pay them back faster than interest accumulates.
PPPPPS: If we had a global 1 child per person policy, then we’d stop at 10 billion people, even if we had LEV right away. There’s tons of stories to be written about all the issues surrounding the implications of making a child when that child potentially has to live until the end of the universe.